Role of fruit volatiles of different guava varieties in attraction and oviposition behaviors of peach fruit fly, Bactrocera zonata Saunders

The present study was conducted to determine the role of guava fruit volatiles in attraction, oviposition and associated fitness parameters of the peach fruit fly, Bactrocera zonata Saunders, which is a key pest of guava and many other fruits. B. zonata female flies’ attraction was observed in a Y-tube olfactometer using fruits of three locally grown guava varieties; Gola, Larkana Small Surahi (LSS) and Larkana Large Surahi (LLS). Female flies showed significantly higher levels of attraction to both un-infested and infested guava fruit odors compared to control (blank). In pairwise comparisons between different fruit varieties, females B. zonata showed significantly greater levels of attraction towards un-infested Gola compared to un-infested LSS, while in the case of the same variety, significantly higher number of flies were attracted to un-infested compared to infested fruit in all three tested varieties. In two-choice oviposition bioassays, B. zonata females made significantly more visits, greater numbers of ovipositions, spent a significantly longer time, and larger numbers of pupae and adults developed on Gola fruits compared to LSS fruits. However, in no-choice bioassays, females made more visits and spent a significantly greater amount of time on LSS compared to Gola and LLS. GC–MS analysis of guava headspace revealed presence of aliphatic and aromatic esters as a dominant group of compounds in both un-infested and fruit-fly-infested guava fruits, with a higher quantity mostly occurring in fruit-fly-infested fruits. Role of guava volatiles is discussed in an ecological context of attraction and oviposition behaviors of adult females and fitness of their offspring.